1. Field of the Invention
The present invention relates to a method of controlling a terminal device, a terminal device operating based on such control, and a memory medium having a program recorded therein for controlling a terminal device. The present invention particularly relates to controlling of a terminal device whereby the terminal device displays results of processing that is performed by a host device.
A display terminal used in a host-terminal system has a screen of 24 rows and 80 columns, for example, and the host system is designed and operated according to such a specification of the screen. Because of development of multi-window environment, however, window sizes on the terminal side are not fixed but vary. In such a system, a system-display screen, a command-input screen, applications, etc., of a host device need to be changed in order to display results of processing on the terminal side when the processing is performed by the host device because the terminal-device screen does not always have a 24-by-80 configuration. A change in a screen size cannot be made only on the terminal side.
2. Description of the Related Art
FIG. 1 is a block diagram showing a configuration of a related-art system.
In a system 1, a host computer 2 is connected to a terminal 3 via a communication line 4.
The host computer 2 includes a program 5, an OS 6, and a communication card 7. The program 5 is designed according to such specifications as a screen is comprised of 24 rows and 80 columns, and operates to supply information to the terminal 3 in response to a request therefrom.
The OS 6 controls execution of programs. The communication card 7 is connected to the communication line 4, and attends to communication with the terminal 3.
The terminal 3 includes a terminal device 8, a display device 9, and a input device 10. The terminal device 8 is connected to the communication line 4, and communicates with the host computer 2 through terminal-emulator processing.
The terminal device 8 includes a communication card 11, an OS 12, and a terminal-emulator program 13.
The communication card 11 attends to communication control of the communication line 4. The OS 12 controls execution of programs installed in the terminal device 8. The terminal-emulator program 13 is used for accessing the host computer 2 to obtain information from the host computer 2 and for displaying the information on the display device 9 in such a size as the host computer 2 determines. For example, the information may be displayed in 24 rows and 80 columns.
The display device 9 is comprised of a CRT, for example, and is connected to the terminal device 8 to display information supplied from the terminal device 8.
The input device 10 is connected to the terminal device 8, and is used for operating the terminal device 8.
In what follows, the terminal-emulator program 13 installed in the terminal device 8 will be described.
FIG. 2 is a block diagram showing functional blocks of a related-art terminal-emulator program.
The terminal-emulator program 13 includes a data-analysis unit 14, a data-display unit 15, a screen buffer 16, a data-input unit 17, and a data-transmission unit 18.
Data supplied from the host computer 2 via the communication line 4 is received and demodulated by the communication card 11. The data demodulated by the communication card 11 is supplied to the terminal-emulator program 13 via a communication driver 19 and a communication-control service 20 under the control of the OS 12.
The data supplied to the terminal-emulator program 13 first goes to the data-analysis unit 14. The data-analysis unit 14 analyzes the data supplied from the communication-control service 20.
The data analysis by the data-analysis unit 14 discriminates commands from display information. The display information is supplied to the screen buffer 16, where the display information is stored in the form of 24 rows and 80 columns as is so designed by the host computer 2. The data-analysis unit 14 further determines whether a command supplied from the host computer 2 is a write command, an erase command, or a read command.
When the write command or the erase command is identified by the data-analysis unit 14, the write command or the erase command is supplied to the data-display unit 15.
In accordance with the command supplied from the data-analysis unit 14, the data-display unit 15 controls the display device 9 via a system-control unit 21, and displays on the display device 9 the 24-by-80 information stored in the screen buffer 16.
The data-input unit 17 receives information about a display area or information about changes in displayed contents via the system-control unit 21 when such information is sent from the input device 10 comprised of a keyboard and a mouse, for example. The received information is supplied either to the data-display unit 15 or to the screen buffer 16. The information about a display area is sent to the data-display unit 15. The data-display unit 15 controls which area portion of the 24-by-80 information is displayed on the display device 9 according to the supplied information about a display area.
The information about changes in displayed contents is supplied to the screen buffer 16. The contents of the screen buffer 16 are changed accordingly.
When a read command is supplied from the host computer 2 to the data-analysis unit 14, the data-analysis unit 14 forwards the read command to the data-transmission unit 18.
Upon receiving the read command, the data-transmission unit 18 sends the information stored in the screen buffer 16 to the host computer 2 via the communication-control service 20, the communication driver 19, the communication card 11, and the communication line 4.
FIG. 3 is an illustrative drawing for explaining operations of the related-art terminal-emulator program.
When receiving the display information from the host computer 2, the terminal-emulator program 13 stores the display information in the screen buffer 16 via the data-analysis unit 14. The display information stored in the screen buffer 16 is mapped to a display screen by the data-display unit 15 according to the information about a display area when the information about a display area is sent from the input device 10 via the data-input unit 17. The mapped display information is supplied to the display device 9 via the system-control unit 21.
For example, as shown in the screen buffer 16 of FIG. 3, the display information may be comprised of xe2x80x9cABCxe2x80x9d starting from column 3 at line 1, xe2x80x9cDEFxe2x80x9d starting from column 40 at line 12, and xe2x80x9cGHIxe2x80x9d starting from column 78 at line 24.
Where an instruction to display the whole display area is given from the input device 10, the 24-by-80 information stored in the screen buffer 16 is mapped in its entirety as shown in a logical screen 15a of the data-display unit 15. In this case, therefore, all the character strings xe2x80x9cABCxe2x80x9d, xe2x80x9cDEFxe2x80x9d, and xe2x80x9cGHIxe2x80x9d stored in the screen buffer 16 are displayed on the display device 9 as shown in FIG. 3 as a window W1.
Where an instruction given from the input device 10 indicates a display area as columns 35-45 of row 12, a portion from column 35 to 45 at line 12, i.e., xe2x80x9cDEFxe2x80x9d, is mapped from the display information stored in the screen buffer 16 as shown in a logical screen 15b of the data-display unit 15. On the display device 9, therefore, only the center portion xe2x80x9cDEFxe2x80x9d of the display information stored in the data-display unit 15 is displayed as shown in FIG. 3 as a window W2.
FIGS. 4A through 4C are illustrative drawings for explaining a display screen of the related-art terminal. FIG. 4A shows a screen for displaying the whole, and FIG. 4B shows a screen for displaying a part. FIG. 4C shows the contents of the screen buffer 16.
As shown in FIGS. 4A and 4B, a display screen includes a title bar 31a, a menu/tool bar 31b, a contents-display field 31c, a status-display field 31d, and a scroll bar 31e. 
The title bar 31a shows a title of the displayed screen. The menu/tool bar 31b provides various menu/tool buttons for editing purposes and for switching of windows or the like.
The contents-display field 31c displays a selected area of the display information stored in the screen buffer 16 as the area is selected by the data-display unit 15. The status-display field 31d displays line numbers of the lines displayed in the contents-display display field 31c. The scroll bar 31e appears in the case of partial display, and is used for moving the area of display.
An instruction to display the whole display information stored in the screen buffer 16 may be given by operating the menu/tool bar 31b. In response to such an instruction, the contents-display field 31c shows the entirety of the display information stored in the screen buffer 16 as shown in FIG. 4A. That is, the display information from line 1:column 1 to line 24:column 80 is displayed.
When an instruction to display a portion of the display information stored in the screen buffer 16 is given by operating the menu/tool bar 31b, the contents-display field 31c displays a portion of the display information stored in the screen buffer 16, e.g., a portion from line 3:column 1 to line 23:column 80 as shown in FIG. 4B.
In the related-art terminal-emulator program, only the contents of the screen buffer 16 can be displayed. When a next display screen is to be displayed, display information is newly obtained from the host computer 2, and the newly obtained display information is written over the existing display information in the screen buffer 16.
When a previous display screen is needed, the display information of the previous display screen is obtained again from the host computer 2, and is written over the existing display information in the screen buffer 16.
In this manner, the terminal-emulator program stores display information in the screen buffer when the display information is supplied from the host computer 2, and displays what is stored in the screen buffer 16. When there is a need to take a look at a previous screen while the display information currently shown on the screen is being edited, the editing is stopped, and the display information edited halfway through is stored in the host computer 2. Then, display information of the previous screen is obtained from the host computer 2, and is stored in the screen buffer 16. When use of this display information is finished, the display information is again stored in the host computer 2. Then, the display information of the original screen is obtained from the host computer 2, and is stored in the screen buffer 16. The editing process is resumed with respect to the display information shown on the screen. In this manner, the whole series of procedure is complex, and does not provide decent manipulability.
In the related-art terminal-emulator program, a screen display operation is not really designed to handle multi-window display in that there is a need to constantly maintain consistency with the host computer 2. This gives rise to a problem that the manipulability of the terminal device is not satisfactory.
Accordingly, there is a need for a scheme for controlling a terminal device which can provide a terminal device with decent manipulability.
Accordingly, it is a general object of the present invention to provide a scheme for controlling a terminal device which can satisfy the need described above.
It is another and more specific object of the present invention to provide a scheme for controlling a terminal device which can provide a terminal device with decent manipulability.
In order to achieve the above objects according to a first aspect of the present invention, a method of controlling a terminal device which receives display information from a host device and displays the display information on a screen includes the steps of dividing the screen into a plurality of areas, displaying newest display information supplied from the host device in a predetermined one of the areas, and displaying previous display information in one or more remaining areas, the previous display information having been supplied from the host device and once displayed as the newest display information in the predetermined one of the areas.
In the method described above, the newest display information sent from the host device is displayed along with the previous display information. When operating the terminal device, therefore, an operator can constantly refer to the previous display information. This helps to achieve reliable user operation of the terminal device.
According to a second aspect of the present invention, the method as described as the first aspect is such that the one or more remaining areas are dedicated for displaying of the previous display information.
In the method described above, since the previous display information is displayed on the areas dedicated for displaying the previous display information, it is easy to discern the previous information from the newest information.
According to a third aspect of the present invention, the method as described as the first aspect further includes a step of deleting oldest display information among the previous display information displayed in the one or more remaining areas when the newest display information arrives from the host device.
According to a fourth aspect of the present invention, the method as described as the third aspect further includes the steps of arranging the one or more remaining areas in a chronological order, and shifting the previous display information in the one or more remaining areas from one area to a next area toward a chronologically older direction each time the newest display information arrives from the host device.
According to a fifth aspect of the present invention, the method as described as the first aspect further includes the steps of selecting display information, displaying the selected display information in one of the one or more remaining areas, and deleting, from the screen, oldest display information among the previous display information except for the selected display information when the newest display information arrives from the host device.
According to a sixth aspect of the present invention, the method as described as the fifth aspect further includes the steps of arranging the one or more remaining areas in a chronological order, except for the one of the one or more remaining areas, and shifting the previous display information in the chronologically arranged areas from one area to a next area toward a chronologically older direction each time the newest display information arrives from the host device.
According to a seventh aspect of the present invention, the method as described as the first aspect is such that the step of dividing the screen is performed upon a request from a user operating the terminal device.
The methods described above can be practiced by a terminal device which includes a first memory that stores newest display information supplied from the host device, a second memory that stores previous display information that has been supplied from the host device and once stored as the newest display information in the first memory, and a control unit that divides the screen into a plurality of areas, and displays the newest display information in a predetermined one of the areas and the previous display information in one or more remaining areas.
Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.